Metering pump



ug- 20, 1968 R. M. Pr-:TRuccl ETAL 3,397,542

METERING PUMP 5 Sheets-Sheet 1 Filed Nov. 18, 1966 WAT/5@ 500615Z Aug. 20, 1968 R. PETRuccu ETAL 3,397,642

METERING PUMP 3 Sheets-Sheet 2 Filed Nov. 18, 1966 INVENTORS BY W Mw Aug. 20, 1968 R. M. Pr- 'rRuc-cl ETAL 3,397,642

METERING PUMP INVENT ORS BY E ATTORNEY United States Patent() 3,397,642 METERING PUMP Raymond M. Petrucci, Waterbury, and Theodore C.

De Paola, Meriden, Conn., assignors to American Machine & Foundry Company, a corporation of New Jersey Filed Nov. 18, 1966, Ser. No. 595,479 6 Claims. (Cl. 103-38) ABSTRACT F THE DISCLOSURE A pump for metering small quantities of chemicals in a liquid feed including a piston-pump, motor means for operating the pump and means for adjusting the stroke of the piston.

This invention relates to metering pumps, and more particularly, it concerns an adjustable stroke pump construction of the type used principally, though not exclusively, in private and small community water supply systems to inject accurately controlled amounts of treating fluids into a ow line through which water is pumped from its source, such as a well, lake or spring, t-o a storage reservoir or tank from which it is drawn for use.

Many diverse types of metering pumps have been employed to introduce or meter small quantities of various chemical solutions to a fluid to be treated, such as water, as it is pumped through a line. The chemical solution in most instances is a sterilizing fluid, such as chlorine, though other treating solutions might be added to water depending on the particular needs dictated by local water supplies. The amount or quantity of such treating fluids to be added will vary due to the conditions of the water source, the flow capacity of the pipe line into which the treating solution or chemical is injected, and in some instances, the wishes or tastes of the user o'f the treater water. Accordingly, it is necessary that such treating fluid metering pumps be adjustable over a fairly wide ran-ge and also to Within closely defined limits. Further, the adjusted capacity of the metering pump must be maintained for long periods of time without significant attention.

In accordance with the present invention, an improved treating fluid metering pump is provided in which a displacement element, preferably a flexible diaphragm, is operably disposed in a pump chamber to be driven during its displacement stroke by an electric motor through an eccentric cam and follower, the latter being connected to the diaphragm. The return stroke of the diaphragm is effected by a spring tending to urge the follower yieldably against the eccentric drive cam. To adjust the length of pumping stroke through which the diaphragm is moved, an eccentric stop, having substantially the same radial configuration as the drive cam, is supported about the rotational axis of the drive cam and adjustable angularly to any one of several indexed positions. An abutment member carried with the diaphragm and drive cam follower engages the eccentric stop to determine the intake position of the diaphragm. Thus, the pump stroke of the diaphragm is established by the maximum intake or return position thereof, which in turn, is established by the angular position of the eccentric stop.

Among the objects o'f the present invention are: the provision of an improved adjustable metering pump of the type referred to which is adjustable in accurately defined increments through a wide range of capacity; the provision of an adjustable metering pump which is ruggedly constructed so as to require a minimum of maintenance; the provision of an improved adjusting mechanism for metering pumps of the type referred to, by which the stroke capacity of the pump may be easily adjusted and maintained in its adjusted position; and the 3,397,642 Patented Aug. 20, 1968 ICC provision of an adjusting device for metering pumps of thetype referred to, which is easy to install and calibrate to achieve a desired pump capacity in increments between zero and maximum.

Other objects and further scope of applicability o'f the present invention will become apparent from the detailed description to follow taken in conjunction with the accompanying drawings in which:

FIG. 1 is a side elevation of a pump of this invention;

FIG. 2 is a cross-section taken on line 2-2 of FIG. 1;

FIG. 3 is a cross-section taken on line 3 3 of FIG. 2;

FIG. 4 is a cross-section taken on line 4-4 of FIG. 2; and,

FIG. 5 is a schematic View illustrating a water supply system in which the adjustable pump of this invention may be used.

As shown in the drawings, the pump structure of this invention includes a frame 1G in the form of an integral casting which supports an outer covering or housing 12 as well as the remaining operating components of the pump to be described below. A re-agent head 14, secured to the frame 10 by suitable means such as machine screws 16, is shaped to dene a pump chamber 18 having a inlet port 20 and an outlet port 22. Check valves 24 and 26 are arranged in the inlet and outlet ports 20 and 22, respectively, in accordance with conventional practice. A displacement element in the form of a flexible diaphram 28 is secured in place over the pump chamber 18 by engagement between the re-agent head 14 and an apertured boss 30 formed in the frame 10. Thus, it will be appreciated that as the displacement element or diaphragm 28 is moved along an axis 32 outwardly of the chamber 18 to an intake position, fluid will pass into the chamber 18 through the inlet port valve 24. Upon movement of the diaphragm into the chamber to a displacement position, the fluid will be displaced outwardly through the outlet port 22 and the outlet port valve 26.

To effect the aforementioned pumping operation of the displacement element 28, an electric motor 34, having a gear reduction mechanism 36 with an output or drive shaft 38, is secured to a transversely extending wall portion 40 on the frame 10. The drive shaft 38 is rotatable, therefore, about an axis 42 and carries a circular cam eccentric 44 having a bearing ring 46 on its peripheral surface. The cam 44 is secured to the shaft 38 by suitable means such as a set screw 47. The bearing ring on the cam 44 engages a following pin 48 secured to a stud 50 by a tapped portion 52 of an abutment member 54 and a set screw 56. The stud 50, as shown in FIGS. .2 and 3, has a head 57 embedded in the diphragm 28. The follower 48 is guided for reciprocal movement along the axis 32 by a bore 58 in a bracket member 60. A helical compression spring 62, acting between the bracket and a head 64 on the follower pin, urges the follower 48 yieldably against the cam bearing 46.

The bracket 60 is also secured to the wall portion 40 of the frame, such as by screws 66, and is formed with a cylindrical boss 68 extending along the drive shaft axis 42 and concentric therewith. An indicator knob 70 is nonrotatably fixed to the outer end of the boss 68 by a screw 72 and complementating axial lugs 74 formed respectively on the inner end of the indicator knob shank 75 and the outer end of the cylindrical boss 68.

An adjustment knob 76 formed integrally on a centrally apertured hub 80 is rotatably supported by the boss 68 and the shank 75 of the indicator knob 70. The inwardly extending end of the hub 80 is formed with an eccentric portion 82 having a radial shape substantially the same as that of the drive cam 44. Also, it will be noted that both the indicator knob 70 and the adjustment knob 76 are formed with complementing radially disposed teeth 84 retained in engagement by a compression spring 86 yieldably urging the adjustment knob 76 outwardly against the indicating knob 70. Hence, the adjustment knob 76 is secured against rotation relative to the indicating knob 70 and thus against rotation about the axis 42 by the teeth 84. When, however, it is decided to adjust the knob 76, it may be moved inwardly against the bias of the spring 86, rotated to the desired position, and then permitted to move outwardly so that the teeth 84 once more anchor it against rotation.

As shown in FIGS. 2 and 4 of the drawings, the abutment member 54 is shaped to establish an arm 88 extending in parallel with the pump axis 32 and offset from the axis 32 so that the terminal or abutting end 90 thereof is in a position to engage the eccentric portion 82 on the adjustment knob hub 80. The arm 88 is guided for reciprocation with the follower 4S and diaphragm 28 by a pair of spaced lugs 92 projecting from the bracket 60. Also, it will be noted that the length of the arm 88 is such that the abutment end 90 thereof is spaced from the drive axis 42 by the same distance as the drive cam engaging surface on the follower pin head 64. Since, as aforementioned, the eccentric portion 82 has the same configuration as the drive cam 44, engagement of the arm 88 with the eccentric portion 82 will have no effect on the length of the pumping stroke when the knob 76 is adjusted so that eccentricity of the hub portion 82 is aligned with the pump axis 32 and positioned on the opposite side of the drive axis 42 from the diaphragm 28. Conversely, when the adjustment knob 76, and thus the hub portion 82 is rotated through 180 from the position aforementioned, the arm 88 and thus the follower pin 48 will be moved to a position where the latter is retained out of operative contact with the drive cam 44. Thus, it will be appreciated that in the first mentioned position of the hub portion 82, maximum pump capacity is achieved, whereas in the latter position, zero pump capacity results as the motor 34 and cam 44 continue to rotate. Moreover, any intermediate capacity may be achieved by adjusting knob 76 as above mentioned between the extreme positions, since the intake position of the diaphragm and thus the length of pump stroke is governed by engagement of the arm 88 with the adjustably fixed eccentric hub portion 82. Also, as is shown in FIG. 1 of the drawings, this capacity may be indicated by the alignment of a pointer 94 carried by the adjustment knob 76 with a scale 96 on the indicator knob 70.

The manner in which the metering pump of this invention may be used to introduce various quantities of a chemical solution to a water supply system is depicted schematically in FIG. 5 of the drawings. As shown, the pump inlet 20 is connected to a supply of chemical solution 98, whereas the outlet 22 is connected by a line 100 and fitting 102 to the discharge line 104 of a pump 106, which in turn draws water from a suitable source such as a well 108. In accordance with conventional practice, the pump 106 is driven by an electric motor 110 under the control of a pressure responsive switch 112 mounted on a storage tank 114. The motor 34 of the metering pump is also connected to the switch 112 so that it will be operated at all times when the main water pump motor 110 is operated. Since the volume of water passing through the discharge line 104 is relatively constant during operation of the pump 106, any desired portion of chemical may be injected by the metering pump by adjusting the knob 76 in the manner described above.

It will be appreciated that the present invention provides an accurately adjustable metering pump by which the above stated objectives are completely fulfilled. It also will be appreciated that variations in the pump construction described herein can be made without departing from the true spirit of the present invention. Accordingly, it is expressly intended that the foregoing description is illustrative of a preferred embodiment only, not limiting, and that the true spirit and scope of the present invention is to be determined by reference to the appended claims.

The invention claimed is:

1. An adjustable stroke metering pump comprising: means defining a pump chamber having inlet and outlet ports; a reciprocal displacement element operably disposed in said chamber for movement between a displacement position and an intake position; drive means for moving said displacement element between said positions, said drive means comprising a motor, a cam eccentric connected to said motor for rotation about an axis normal to the direction of displacement element movement, a cam follower connected to said displacement element, and resilient means to urge said follower toward engagement with said cam eccentric; and adjustable means for changing said intake position to vary the length of stroke of said displacement element in moving between said positions, said adjustable means comprising an eccentric stop rotatable about said axis and having a radial configuration substantially the same as that of said cam eccentric, means to fix the adjusted rotational position of said eccentric stop, and abutment means movable with said displacement element to engage said stop and thereby establish said intake position.

2. The apparatus recited in claim 1 in which said adjustable means includes further, a fixed indicating knob having a cylindrical shank portion disposed concentrically on said fixed axis, an adjustment knob rotatable with said eccentric stop, and means to fix the relative positions of said knobs.

3. The apparatus recited in claim 2 in which said last mentioned means includes radially disposed, axially er1- gaging teeth on said knobs, and spring means to yieldably bias said teeth into engagement.

4. The apparatus recited in claim 2 including scale indicia on said knobs to indicate the relative position thereof.

5. An adjustable stroke metering pump comprising: a supporting frame; means on said frame to establish a pump chamber having inlet and outlet ports; a reciprocal displacement element operably disposed in said chamber for movement along a first axis between a displacement position and an intake position; a motor supported on said frame and having a drive `shaft rotatable about a second axis normal to said first axis, a drive cam mounted eccentrically on said shaft for angular movement about said second axis; a cam follower connected to said displacement element; bracket means on said frame and having guide means to support said cam follower for movement along said first axis; spring means to urge said follower yieldably toward said drive cam; a cylindrical boss on said bracket means, said boss being concentric with said second axis; a stroke adjustment knob rotatably supported by said boss; said knob having an eccentric stop portion thereon with a radial configuration similar to that of said drive cam; indexing means to fix the rotational position of said adjustment knob; and abutment means movable with said displacement element and said cam follower to engage said eccentric stop portion and establish said intake position.

6. The apparatus recited in claim 5 in which said abutment means includes an arm portion disposed in offset parallel relation to said first axis, and means on said bracket to guide said arm portion during movement thereof with said cam follower.

References Cited UNITED STATES PATENTS 2,414,617 1/1947 Summers 103-38 2,560,283 7/1951 Giesey 103-38 3,036,525 5/1962 Schulze 103-38 3,130,909 4/1964 Sanborn 103-38 3,301,189 1/1967 Kling 103--38 ROBERT M. WALKER, Primary Examiner. 

